Minimum Energy Tracking Loop With Embedded DC-DC Converter

An energy minimization loop, with on-chip energy sensor circuitry, that can dynamically track the minimum energy operating voltage of a digital circuit with changing workload and operating conditions occupies 0.05mm2 in 65nm CMOS. The DC-DC converter that enables this minimum energy operation can deliver load voltages as low as 250mV and achieved an efficiency >80% while delivering load powers of the order of 1µW and higher from a 1.2V supply.